1. Electric Cells Section 5.3 (p. 217 – 226)

2. (chemical) Cells i.e. batteries Direct current (DC) devices Electron flow = leave negative side, re-enter positive terminal Conventional current = positive termina  negative terminal Higher potential = positive terminal Primary Cell Internal cell Used until power supply is exhausted Secondary Cell Rechargeable When exhausted, charger reverses chemical reaction to recreate original chemical composition

3. Research-based Journal Entry (#1) What are the chemicals used in a primary cell dry-cell battery? Which is associated with the positive terminal and which is associated with the negative terminal? What is different about a rechargeable battery?

4. Cell Capacity If two cells have the same chemical composition, they will each be able to generate the same emf (electromotive force) for a circuit. Capacity: the measure of the ability of a cell to release its charge. High rate of discharge = short-lasting cell Low rate of discharge = long-lasting cell Determined by the constant current that can be supplied during discharge Units = Amp-hours (Ah)

5. Lab set-up Select someone in the class to set up a scenario such as is found on page 221 of your textbook. Use a LabQuest, a 1.5 V battery, a light-bulb, and a Vernier Voltage Sensor. We will be leaving this set up and collecting data overnight. (set the data collection accordingly—for about 30 hours, with data collected every minute or so) If you are not the one setting it up, you need to check on it. Journal entry for everyone: Sketch a circuit diagram of the set-up, and predict what the graph of terminal voltage as a function of time will look like for the next 26 hours. Leave space for a sketch of the actual results.

6. eMF Electromotive Force: the open circuit potential difference across the terminals of a power source The terminal voltage when no current is supplied The energy per unit charge made available (supplied) by the source Internal Resistance Present in all electrical cells, to some extent Consumes some of the potential from the eMF, so the terminal voltage will decrease when current is running through a circuit. eMF = terminal voltage + potential drop across internal resistance

7. Journal entry #3: Sources of eMF In no more than 2 sentences, summarize how the following sources will generate eMF to supply a circuit with electrical power, and give 1 example of an application where/how this source is used: Electromagnetic Chemical Photoelectric Piezoelectric Thermoelectric Hint: there is an extra set of notes on the website to help with this…